New lessons from knockout mice: The role of serotonin during development and its possible contribution to the origins of neuropsychiatric disorders

Serotonin (5-HT) modulates numerous processes in the central nervous system that are relevant to neuropsychiatric function and dysfunction. It exerts significant effects on anxiety, mood, impulsivity, sleep, ingestive behavior, reward systems, and psychosis. Serotonergic dysfunction has been implicated in several psychiatric conditions but efforts to more clearly understand the mechanisms of this influence have been hampered by the complexity of this system at the receptor level. There are at least 14 distinct receptors that mediate the effects of 5-HT as well as several enzymes that control its synthesis and metabolism. Pharmacologic agents that target specific receptors have provided clues regarding the function of these receptors in the human brain. 5-HT is also an important modulator of neural development and several groups have employed a genetic strategy relevant to behavior. Several inactivation mutations of specific 5-HT receptors have been generated producing interesting behavioral phenotypes related to anxiety, depression, drug abuse, psychosis, and cognition. In many cases, knockout mice have been used to confirm what has already been suspected based on pharmacologic studies. In other instances, mutations have demonstrated new functions of serotonergic genes in development and behavior.     

Pavlov in America: a heterodox approach to the study of his influence

This work presents a critical analysis of Pavlov's influence that goes beyond the conventional view: that which reduces his influence in American psychology to the behaviorism of Watson and Hull. In order to understand the nature of the Russian physiologist's influence in American psychology, we propose a distinction between three approaches to it: 1) the symbolic approach, on representing a model of the possibility of constructing an objective psychology; 2) the methodological approach, given the importance of the technique of conditional reflexes; and 3) the theoretical approach, which is derived from his theory of higher nervous activity. This perspective permits us to suggest that most of Pavlov's influence on behaviorism was of a symbolic and methodological nature--though the methodological influence also reached other authors that did not belong to the behaviorist traditions, as was the case of Mateer. As far as the theoretical influence is concerned, our work proposes that it is more visible in authors such as Gantt and Liddell, or even in authors such as Boldirev, Director of the Pavlovian Laboratory at the Battle Creek Sanitarium in Michigan. The case of Gantt is especially interesting because, in addition to his important contributions, he played an essential role in the foundation of the Pavlovian Society, and the journal Conditional Reflex. What our work proposes is that to understand the nature of Pavlov's influence in American psychology it is necessary to take into account the very characteristics of that psychology: its pragmatic interests, its methodological rigor, the dominant systems of neo-behavioral theory and the changes that occurred after the Second World War.     

Social psychology of mental health: the social structure and personality perspective

Previous research has revealed a persistent association between social structure and mental health. However, most researchers have focused only on the psychological and psychosocial aspects of that relationship. The present paper indicates the need to include the social and structural bases of distress in our theoretical models. Starting from a general social and psychological model, our research considered the role of several social, environmental, and structural variables (social position, social stressors, and social integration), psychological factors (self-esteem), and psychosocial variables (perceived social support). The theoretical model was tested working with a group of Spanish participants (N = 401) that covered a range of social positions. The results obtained using structural equation modeling support our model, showing the relevant role played by psychosocial, psychological and social, and structural factors. Implications for theory and intervention are discussed.     

Prevalence of Child and Adolescent Exposure to Community Violence

Emerging as one of the most significant health issues facing American youth today, child and adolescent exposure to community violence has generated much interest across multiple disciplines. Most research to date has focused on documenting the prevalence of community violence and the emotional and behavioral ramifications. This paper provides an overview of the current literature regarding prevalence of youth exposure to community violence, and identifies those areas where further research is warranted. In addition to examining overall rates of community violence exposure, this paper reviews the prevalence of different types of community violence, such as weapon use, physical aggression, and crime-related events. Predictors of community violence exposure, including gender, age, race, socioeconomic status, behavior patterns, and geography, are discussed.     

Ethnic identity, self-esteem, and ethnocentrism: a study of social identity versus multicultural theory of development

Social identity theory (SIT) proposes that the more strongly individuals identify with their group, the less favorable attitudes they hold toward dissimilar groups. In contrast, multicultural theory proposes that affirmation toward one's group--particularly with respect to ethnicity--should correspond with higher levels of acceptance toward dissimilar groups. These competing theories were examined with 486 non-Hispanic White, African American, and Hispanic/Latino university students to determine if support would be found for either theory. Consistent with SIT, levels of ethnic identity correlated significantly with levels of ethnocentrism for Whites and Hispanics but not for African Americans. African Americans obtained significantly higher ethnic identity and self-esteem scores than the other 2 groups. Implications of the findings are discussed.     

The effects of depression on the emotional responses of Spanish-speaking Latinas

Emotional responses (physiology, self-report, and facial expression) of 12 depressed and 10 nondepressed Spanish-speaking Latinas during sad and amusing film clips of human and animal content were compared. Depressed Latinas demonstrated less electrodermal reactivity across all the film clips and displayed fewer social smiles during the amusing-human film clip than nondepressed Latinas. No differences emerged for cardiovascular measures, reports of emotion, or facial expressions of happiness and negative emotion. Observed differences in electrodermal reactivity are similar to results from previous studies of Anglo Americans, suggesting that reduced electrodermal activity may be linked to depression across cultures. The findings also suggest that, for Latinas, depression may selectively alter expressions that serve interpersonal functions.     

Are exercise social-cognitive factors and behaviours different for adults with diabetes? A randomized community sample

Exercise plays a key role in the prevention and delay of the onset of Type 2 diabetes and in the management of this disorder. To determine if there are differences in key social-cognitive determinants of exercise and self-reported physical activity levels between adults with diabetes and those without the condition, a random selected sample of adults was surveyed. A telephone interview assessed physical activity behaviour and key social-cognitive constructs from major health behaviour change theories/models. The mean energy expenditure was not significantly different between the diabetes (n?=?46) and the non-diabetes (n?=?1556) groups. The diabetes group reported significantly lower scores for self-efficacy and perceived behavioural control, but higher for fear of, and vulnerability to, general health and cardiovascular disease threat. The data suggest that it may not be necessary to promote health threat messages, as threat is already high for this diabetes population and studies have shown that excess threat does not promote recommended exercise and health behaviours. Instead, the low levels of self-efficacy and perceived behavioural control among those with diabetes emphasize the importance of designing specific strategies (e.g., skills, incremental success) to increase their self-confidence in undertaking physical activity.     

Causal attributions and blame: associations with mothers' adjustment to the birth of a child with Down syndrome

The main purpose of this study is to explore the associations between causal attributions to others, blaming others and mothers' adjustment to the birth of a child with Down syndrome (DS). Participants (n?=?214) rated causal attributions to others and blaming others, and completed five measures of adjustment: anger, anxiety, depression, parenting stress, and attitudes towards the child. The adjustment of three groups of mothers was compared: (i) those who made no attributions to others (ii) those who made causal attributions but did not blame, and (iii) those who blamed others. Four years after the births of their children with DS, 16% of mothers blamed others and 17% made causal attributions but did not blame others for this outcome. Those who blamed others had higher levels of anger, anxiety, depression, parenting stress and more negative attitudes towards their children with DS than did those who made causal attributions but did not blame, and those who made who made no attributions to others. The adjustment of the latter two groups did not differ. Investigating blame rather than causal attributions may be a more fruitful area for future research aimed at understanding and facilitating adjustment to illness and other negative life events.     

How conscious experience and working memory interact

Active components of classical working memory are conscious, but traditional theory does not account for this fact. Global Workspace theory suggests that consciousness is needed to recruit unconscious specialized networks that carry out detailed working memory functions. The IDA model provides a fine-grained analysis of this process, specifically of two classical working-memory tasks, verbal rehearsal and the utilization of a visual image. In the process, new light is shed on the interactions between conscious and unconscious aspects of working memory.